JP3959096B2 - New flexible polyurethane foam - Google Patents

Description

The present invention relates to a flexible polyurethane foam and a method for producing such a flexible polyurethane foam.
Flexible polyurethane foams are widely known. Such foams exhibit relatively high resilience, a relatively low modulus, a relatively high sag factor, and a relatively low hysteresis loss.

Such foams further exhibit a major glass-rubber transition below the ambient temperature, generally in the temperature range of -100 ° C to -10 ° C. Polyether and polyester polyols of relatively high molecular weight commonly used in such foams are responsible for the sub-ambient glass transition temperature (Tg ^s). These polyether and polyester polyols are often referred to as soft segments. Exceeds tg ^s, form, to the softening and / or melting of the isocyanate-derived urethane / urea clusters ( "hard domains") takes place, indicating the typical soft characteristics.

This softening and / or melting temperature (Tg ^h and / or Tm ^h ) often coincides with the onset of thermal collapse of the polymer segment. The flexible polyurethane foam typically has a Tg ^h and / or Tm ^h higher than 100 ° C. and may even exceed 200 ° C. In tg ^s, sharp decrease of the modulus of the flexible foam is observed. Between Tg ^s and ^{Tg h} / Tm h, although the elastic modulus remains constant much even if the temperature ^rises, a significant decrease in the Tg ^h / Tm h the modulus is again performed. Way of expressing the presence of tg ^s, the dynamic mechanical thermal analysis (Dynamic Mechanical Thermal Analysis) -100 ℃ conforming to (ISO / DIS DMTA measured by 6721-5) and + 25 ° C. and a Young's storage modulus at (Young's storage modulus) to measure the ratio of E ′. For conventional flexible polyurethane foam, the ratio E ′ (−100 ° C.) / E ′ (+ 25 ° C.) is at least 25.

Another characteristic of Tg ^s according to DMTA (ISO / DIS 6721-5) is that for conventional flexible polyurethane foams, the Young loss modulus E ″ / Young storage modulus E ′ over the temperature range of −100 ° C./+25° C. The maximum value of the ratio (tan δ _max ) generally varies within the range of 0.20 to 0.80. Young loss modulus E ″ is also measured by DMTA (ISO / DIS 6721-5).

  In this specification, the polyurethane foam has a rebound resilience [preflex conditioning is not applied, only one rebound value is measured per sample, and the test piece is 23 ° C. ± 2 ° C. (relative humidity 50 ± 5%) is considered soft when measured according to ISO 8307 at least 40%, preferably at least 50%, most preferably 55-85% in at least one of the three dimensions . In this specification, when ISO 8307 is cited, this means the test described above including the proviso. Such flexible foam preferably has a Young storage modulus at 25 ° C. of 500 kPa or less, more preferably 350 kPa or less, most preferably 10-200 kPa (Young storage modulus measured by DMTA according to ISO / DIS 6721-5). Have. Furthermore, such flexible foams preferably have a sag factor (CLD 65/25) of at least 2.0, more preferably at least 3.5, most preferably 4.5 to 10 (measured according to ISO 3386/1). . Furthermore, such flexible foams preferably have a CLD hysteresis loss (ISO 3386/1) of less than 55%, more preferably less than 50% and most preferably less than 45%.

As used herein, a polyurethane foam is rigid if the rebound resilience is less than 40% when measured according to ISO 8307 at a free rise core density of ^{3 to} 27 kg / m ^3. Considered.

The ratio of E ′ (−100 ° C.) / E ′ (+ 25 ° C.) of such a rigid foam is preferably 1.3 to 15.
Conventional flexible foams comprise a polyisocyanate and a relatively high molecular weight isocyanate-reactive polymer, often a polyester or polyether polyol, optionally in the presence of a blowing agent, with a further limited amount of a relatively low molecular weight chain extender. Manufactured by using a crosslinking agent and optionally further reacting with additives such as catalysts, surfactants, flame retardants, stabilizers and antioxidants. The relatively high molecular weight isocyanate-reactive polymer generally represents the highest weight portion of the foam. Such flexible foams can be produced according to a one-shot process, a quasi- or semi-prepolymer process or a prepolymer process. Such flexible foams can be molded foams or slabstock foams and can be used as cushioning materials in furniture and automobile seats and mattresses, as hydrophilic foams in diapers and as packaging foams. Furthermore, they can be used for acoustic applications, for example as sound insulation materials. Examples of prior art of these conventional flexible foams are EP-10850, EP-22617, EP-111121, EP-296449, EP-309217, EP-309218, EP-392788 and EP-442631.

  Conventional rigid foams are produced in a similar manner, provided that the polyisocyanate often has high isocyanate functionality, uses less high molecular weight polyols, and increases the amount and functionality of the crosslinker. Is done.

WO 92/12197 describes energy absorption, continuous foaming, water-foaming (water) obtained by reacting in a mold a polyurethane foam formulation comprising a foaming agent and water acting as a cell opener. -blown) rigid polyurethane foams, in which the cured foam remains a molded density of about 32-72 kg / m ³ and a constant deflection of 10-70% when loaded below 70 psi Crush strength. These foams have minimal springback or hysteresis.

  British Patent No. 2,096,616 discloses a directional softened, rigid, closed cell plastic foam. This rigid foam is softened for use in, for example, pipe insulation. Bubbles should remain independent.

  U.S. Pat. No. 4,299,883 discloses a sound-absorbing material produced by compressing a foam having closed cells to such an extent that the foam recovers to 50-66% of its original thickness. By compressing, the bubbles are broken and the foam becomes soft and elastic; this foam can be replaced by felt. This disclosure relates primarily to polycarbodiimide foams.

EP 561216 discloses the production of a foam board with improved thermal insulation, which has a density of 15 to 45 kg / m ³ and a major axis to minor axis length ratio of 1.2 to 1.6. These bubbles are crushed in the thickness direction of the plate. This disclosure actually relates to polystyrene boards. Since this disclosure relates to a foam having improved thermal insulation, the foam actually has closed cells.

EP 641635 describes a method for producing a foam board having a dynamic stiffness of up to 10 MN / m ³ by crushing a board with a density of 17-30 kg / m ³ at least twice to 60-90% of its original thickness. Disclosure. It is preferred to use closed cell polystyrene. The examples show that a crushed polystyrene foam exhibits better thermal insulation than one that is not crushed.

  U.S. Pat. No. 4,454,248 discloses a process for producing a rigid polyurethane foam comprising softening, crushing, re-expanding and completely curing an incompletely cured rigid foam.

Surprisingly, it has been discovered that a completely new type of flexible polyurethane foam is one that does not have a major glass-rubber transition between -100 ° C and + 25 ° C. In a more quantitative aspect, these foams have an E ′ (−100 ° C.) / E ′ (1.3 to 15.0, more preferably 1.5 to 10, most preferably 1.5 to 7.5. + 25 ° C.) ratio. The tan δ _max is less than 0.2 over a temperature range of −100 ° C. to + 25 ° C.

The free rise core density of such foams is in the range of 4-30 kg / m ³ , preferably in the range of 4-20 kg / m ³ (measured according to ISO / DIS 845). The foams according to the invention preferably have a primary glass-rubber transition above 50 ° C., most preferably above 80 ° C.

  The flexible polyurethane foam according to the present invention is produced by reacting a polycyanate with a polyfunctional isocyanate-reactive polymer under foam-forming conditions to obtain a rigid polyurethane foam and then crushing the rigid polyurethane foam. . Furthermore, the present invention relates to a method for producing such a rigid foam and a reaction system comprising components for producing such a foam.

In the context of the present invention, the following terms have the following meanings:
(1) Isocyanate index or NCO index or index:
([NCO] x 100) / [Active hydrogen] (%)
The ratio of NCO groups to isocyanate-reactive hydrogen atoms present in the formulation, given as:

  In other words, the NCO index represents the percentage of isocyanate actually used in the formulation relative to the theoretically required amount of isocyanate to react with the amount of isocyanate-reactive hydrogen used in the formulation.

  It should be noted that the isocyanate index used herein is considered from the standpoint of an actual foaming process that requires an isocyanate component and an isocyanate-reactive component. Isocyanate groups consumed in the pre-stage or active hydrogen consumed in the pre-stage to produce modified polyisocyanates (including isocyanate derivatives such as quasi-prepolymers or semi-prepolymers and prepolymers in the art) (Eg, those that react with isocyanates to produce modified polyols or polyamines) are not considered in the calculation of the isocyanate index. Only free isocyanate groups and free isocyanate reactive hydrogen (including hydrogen in water) present in the actual foaming stage are considered.

  (2) The expression “isocyanate-reactive hydrogen atom” as used herein to calculate the isocyanate index refers to the total amount of active hydrogen in the hydroxyl and amine groups present in the reactive composition; This is because one hydroxyl group contains one reactive hydrogen in order to calculate the isocyanate index in an actual foaming process, one primary amine group contains one reactive hydrogen It means that one water molecule is considered to contain two reactive hydrogens.

(3) Reaction system: A combination of elements in which the polyisocyanate is held in one or more containers separate from the isocyanate-reactive elements.
(4) As used herein, the expression “polyurethane foam” refers to a cellular product obtained by reacting a polyisocyanate with an isocyanate-reactive hydrogen-containing compound using a blowing agent; In particular, water as a reactive blowing agent (including the reaction of water and isocyanate groups, which produces urea bonds and carbon dioxide to produce polyurea-urethane foam), and a polyol as an isocyanate-reactive compound, Includes cellular structure products obtained with amino alcohols and / or polyamines.

  (5) The term “average nominal hydroxyl functionality” is the number average functionality (number of active hydrogen atoms per molecule) of one or more initiators used in their production. Assuming that there is (in fact, often somewhat less because of some terminal unsaturation), the specification herein will indicate the number average functionality (number of hydroxyl groups per molecule) of the polyol or polyol composition. Used in

(6) The term “average” means number average unless otherwise specified.
The foam according to the invention has a polyisocyanate (1), an isocyanate-reactive compound (2) having an average weight of 374 or less and an average number of isocyanate-reactive hydrogen atoms of 2 to 8 and more than 374 Reacting an isocyanate-reactive compound (3) having an average equivalent weight and an average number of 2 to 6 isocyanate-reactive hydrogen atoms with water to form a rigid polyurethane foam and crushing the rigid polyurethane foam Manufactured by.

Furthermore, this invention relates to the reaction system containing the said component. The present invention also relates to a method for producing a rigid polyurethane foam using the above components.
More particularly, the foam according to the invention comprises a polyisocyanate (1), a polyol (2) having a hydroxyl number of at least 150 mg KOH / g and an average nominal hydroxyl functionality of 2-8, from 10 mg to less than 150 mg. Produced by reacting polyol (3) having a KOH / g hydroxyl number of 2 and an average nominal hydroxyl functionality of 2-6 with water to form a rigid polyurethane foam and crushing the rigid polyurethane foam. Is done.

  Suitable organic polyisocyanates for use in the process of the present invention are aliphatic, cycloaliphatic, araliphatic and preferably aromatic polyisocyanates such as 2,4- and 2,6-isomers. Toluene diisocyanates and their derivatives, diphenylmethane diisocyanate, diphenylmethane diisocyanate (MDI) as 2,4′-, 2,2′- and 4,4′-isomers and “crude” or polymeric MDI in the art (Polymethylene polyphenylene polyisocyanate) mixtures with oligomers thereof having an isocyanate functionality greater than 2, urethane groups, allophanate groups, urea groups, biuret groups, carbodiimide groups, uretonimine and / or isocyanurate groups Including existing MDI Variations such as, encompasses any polyisocyanates known in the art for the production of rigid polyurethane foams.

  Isocyanate-reactive compound (2) includes any compound known in the art for this purpose, such as, for example, polyamines, amino alcohols and polyols. Of particular importance for the production of rigid foams are polyols and polyol mixtures having a hydroxyl number of at least 150 mg KOH / g and an average nominal hydroxyl functionality of 2-6. Suitable polyols are described in detail in the prior art and include, for example, reaction products of alkylene oxides such as ethylene oxide and / or propylene oxide with initiators containing 2 to 8 active hydrogen atoms per molecule. . Suitable initiators are for example polyols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butanediol, glycerol, trimethylolpropane, triethanolamine, pentaerythritol, sorbitol and sucrose; for example ethylenediamine, tolylenediamine, Polyamines such as diaminodiphenylmethane and polymethylene polyphenylene polyamine; amino alcohols such as ethanolamine and diethanolamine; and mixtures of such initiators. Other suitable polyols include polyesters obtained by condensation of appropriate proportions of glycols, higher functionality polyols, and polycarboxylic acids. Still other suitable polyols include hydroxyl terminated polythioethers, polyamides, polyester amides, polycarbonates, polyacetals, polyolefins and polysiloxanes. Still other suitable isocyanate-reactive compounds include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butanediol, glycerol, trimethylolpropane, ethylenediamine, ethanolamine, diethanolamine, triethanolamine, and other such initiators. To do. Mixtures of such isocyanate-reactive compounds can be used as well.

  Isocyanate-reactive compounds (3) include any compounds known in the art for this purpose, such as polyamines, amino alcohols and polyols. Of particular importance for the production of rigid foams has a hydroxyl number from 10 mg to less than 150 mg, preferably 15-60 mg KOH / g and an average nominal hydroxyl functionality of 2-6, preferably 2-4, Polyols and polyol mixtures. These high molecular weight polyols are generally known in the prior art, for example reaction products of alkylene oxides such as ethylene oxide and / propylene oxide with initiators containing 2 to 6 active hydrogen atoms per molecule. Include. Suitable initiators are for example polyols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butanediol, glycerol, trimethylolpropane, triethanolamine, pentaerythritol and sorbitol; for example ethylenediamine, tolylenediamine, diaminodiphenylmethane And polyamines such as polymethylene polyphenylene polyamine; amino alcohols such as ethanolamine and diethanolamine; and mixtures of such initiators.

  Other suitable polyols include polyesters obtained by condensation of appropriate proportions of glycols and higher functionality polyols with polycarboxylic acids. Still other suitable polyols include hydroxyl terminated polythioethers, polyamides, polyester amides, polycarbonates, polyacetals, polyolefins and polysiloxanes. Preferred polyols are polyether polyols containing ethylene oxide and / or propylene oxide units, most preferably polyoxyethylene polyoxypropylene polyols having an ethylene content of at least 20% by weight. Other polyols that can be used include dispersions or solutions of addition or condensation polymers in the above types of polyols. Such modified polyols, often referred to as “polymer” polyols, have been described in detail in the prior art, for example, in situ polymerization of one or more vinyl monomers such as styrene and acrylonitrile in polymer polyols such as polyether polyols. Or products obtained by in situ reaction of polyisocyanates with amine- or hydroxy-functional compounds such as triethanolamine in polymer polyols.

The polymer-modified polyols of particular importance according to the invention are the products obtained by in-situ polymerization of styrene and / or acrylonitrile in poly (oxyethylene / oxypropylene) polyols and the poly in oxyethylene / oxypropylene polyols. A product obtained by in situ reaction of an isocyanate with an amino- or hydroxy-functional compound (eg triethanolamine). Polyoxyalkylene polyols containing 5-50% dispersed polymer are particularly useful. A dispersed polymer particle size of less than 50 microns is preferred. Mixtures of such isocyanate-reactive compounds can be used as well.
The relative amounts of isocyanate-reactive compounds (2) and (3) or polyols (2) and (3) can vary widely, but preferably from 0.1: 1 to 4: 1 (w: w) Range.

  The relative amounts of polyisocyanate to be reacted and isocyanate-reactive compound can vary within wide limits. In general, an isocyanate index of 25-300, preferably 30-200, most preferably 40-150 is applied.

Water can be used as a swelling agent to produce the foam. However, if the amount of water is not sufficient to obtain the desired foam density, for example, the use of low pressure or variable pressure, the use of gases such as air, N ₂ and CO ₂ , such as chlorofluorocarbons, hydrofluorocarbons, The use of more conventional blowing agents such as hydrocarbons and fluorocarbons, the action of reacting with any of the other reactive blowing agents, i.e. the components of the reaction mixture, to release the gas that causes the mixture to foam for this reaction And any other known methods for making polyurethane foam, such as the use of an agent and the use of a catalyst that enhances the reaction that results in gas formation, such as a carbodiimide formation enhanced catalyst such as phosphorene oxide. it can. Combinations of these foam forming methods can also be used. The amount of blowing agent can vary widely and depends primarily on the desired density. Water can be used as a liquid at sub-ambient temperatures, ambient or elevated temperatures, and as steam.

  The total amount of polyisocyanate (1), isocyanate-reactive compound (2) and compound (3) or polyol (2) and polyol (3) and water is preferably 100 parts by weight, preferably compound (2) or polyol (2). Is in the range of 2 to 20 parts by weight, the amount of compound (3) or polyol (3) is in the range of 5 to 35 parts by weight, the amount of water is in the range of 1 to 17 parts by weight, and the balance Is a polyisocyanate. This includes other aspects of the invention: cyclic polyisocyanates, more particularly aromatic polyisocyanates, and even more particularly when using MDI or polymethylene polyphenylene polyisocyanates, the content of cyclic residues in the flexible foam. More specifically, the content of aromatic residues is relatively large compared to conventional flexible polyurethane foams. The foam according to the invention preferably has an aromatic polyisocyanate-derived benzene ring content of 30 to 56% by weight, most preferably 35 to 50% by weight, based on the weight of the foam. Since polyols, polymer polyols, flame retardants, chain extenders and / or fillers containing benzene rings can be used, the total benzene ring content of the flexible foam can be increased, and by calculated Fourier transform infrared analysis When measured, it is preferably in the range of 30-70 wt%, most preferably 35-65 wt%.

In addition to polyisocyanates, it is possible to use one or more auxiliaries or additives known per se for the production of isocyanate-reactive compounds and blowing agents, polyurethane foams. Such optional adjuvants or additives include cell stabilizers or surfactants such as siloxane-oxyalkylene copolymers and polyoxyethylene polyoxypropylene block copolymers, urethane / urea catalysts such as tin compounds (eg octanoic acid first Tin or dibutyltin dilaurate) and / or tertiary amines (eg dimethylcyclohexylamine or triethylenediamine) and / or phosphates (eg NaH ₂ PO ₄ and Na ₂ HPO ₄ ), and flame retardants such as halogenated alkyl phosphates (eg Trischloropropyl phosphate), melamine and guanidine carbonates, antioxidants, UV stabilizers, antibacterial and antifungal compounds, and fillers such as latex, TPU, silicates, barium sulfate and calcium sulfate Encompasses um, chalk, glass fibers or beads and polyurethane waste.

  For the implementation of the rigid foam manufacturing process according to the invention, known one-shot, prepolymer or semi-prepolymer methods can be used with conventional mixing methods, and as slab materials, foams for fabrics and in situ foaming applications, spraying Manufacture rigid foams as foams, including foamed foams, frothed foams or laminates with other materials such as hardboard, gypsum board, plastic, paper or metal or with other foam layers can do.

  In many applications, it is convenient to provide the elements for polyurethane production as a preblended composition based on each of the primary polyisocyanate aquabiisocyanate reactive elements. In particular, isocyanate-reactive compositions containing adjuvants, additives and blowing agents in addition to isocyanate-reactive compounds (2) and (3) in the form of solutions, emulsions or dispersions can be used.

Rigid foams are produced by reacting the components and foaming until the foam no longer expands. The foam can then be crushed. However, it is preferred to cool the resulting rigid foam to below 80 ° C., preferably below 50 ° C., most preferably to ambient temperature before crushing. After the rise, foam curing can continue as long as desired. In general, a curing time of 1 minute to 24 hours, preferably 5 minutes to 12 hours is sufficient. If necessary, curing can be carried out at an elevated temperature. The rigid foam (ie before crushing) preferably has a density of ^{3 to} 27 kg / m ³ , most preferably ^{3 to} 18 kg / m ³ .

The produced rigid foam (ie before crushing) has a significant amount of open cells. It is preferable that the bubbles of the rigid foam are mostly continuous.
The crushing can be done by any known method and by any known means. The crushing can be done, for example, by applying a mechanical force to the foam using a flat or preformed surface, or by applying various external pressures.

  In most cases, sufficient mechanical force will be appropriate to reduce the size of the foam in the direction of crushing by 1-90%, preferably 50-90%. If necessary, the crushing can be repeated and / or performed in different directions of the foam. Due to the crushing, the resilience increases considerably in the crushing direction. Due to the crushing, the density of the foam also increases. In general, this increase will not exceed 30% of the density before crushing.

  Since the direction of crushing depends in particular on the density of the foam, the rigidity of the foam, and the type of crushing device used, it is difficult to make the crushing direction more accurate, but those skilled in the art are well aware of the crushing phenomenon of polyurethane foam. Therefore, it is considered that the appropriate crushing method and means can be surely determined by the above guidance if the following examples are further considered.

After crushing, a new flexible foam with special properties is obtained. Despite the fact that the foam is flexible, as mentioned above, the foam does not show a significant change in Young's storage modulus E ′ over the temperature range of −100 ° C. to + 25 ° C. This foam exhibits good flame retardancy even in the absence of flame retardant additives. The oxygen index of foams made from aromatic polyisocyanates is preferably greater than 20 (ASTM 2863). Furthermore, the foam has a Young's storage modulus at 25 ° C. of 500 kPa or less, preferably 350 kPa or less, most preferably 10-200 kPa, and at least 2.0, preferably at least 3.5, most preferably 4.5-10. The sag coefficient (CLD 65/25, ISO 3386/1) is shown. The foam has a CLD hysteresis loss value of less than 55%, preferably less than 50% (this value is represented by the formula:
[(A−B) / A] × 100%
Where A and B represent the area under the stress / strain curve of loaded (A) and unloaded (B) as measured by ISO 3386/1. Still further, these foams can be made with very low or negative Poisson's ratios as measured by a lateral extension test under foam compression. Finally, the compression set values of these foams are generally low, preferably less than 40% (ISO 1856 method A, standard method).

If tg ^h is not too high, it is possible to produce a molded body by using this form thermoforming process. For such thermoforming applications, Tg ^h of the foam is preferably 80 to 180 ° C., most preferably 80 ° C. to 160 ° C..

  Furthermore, the foam exhibits good yield strength properties, such as compression hardness, with good hysteresis, tear strength and durability (fatigue resistance), even at very low densities, without the use of external fillers. In conventional flexible foams, it is often necessary to use large amounts of fillers in order to obtain satisfactory strength properties. Such large amounts of fillers hinder processing due to increased viscosity.

  The foam of the present invention can be used as a cushioning material in furniture, automobile seats and mattresses, as a hydrophilic foam in diapers, as a packaging foam, as a sound insulation and generally as an anti-vibration foam in automobile applications.

The following examples further illustrate the invention.
Example 1
Polymer MDI having an NCO value of 30.7 wt% and an isocyanate functionality of 2.7 (56.6 wt%), an NCO value of 31 wt%, an isocyanate functionality of 2.09 and an uretonimine of 17 wt% A polyisocyanate mixture was prepared by mixing uretonimine modified MDI (43.4 wt%) with a content and 20 wt% 2,4'-MDI content.

  32.2 parts by weight (pbw) of polyethylene glycol 200, 4.5 pbw of ethylene glycol, 42.6 pbw of EO / PO polyol (nominal functionality 2, EO content 20.2% by weight (all chipped) Isocyanate) by mixing tipped) and a hydroxyl number of 30 mg KOH / g), 5.5 pbw diethanolamine, 14.5 pbw water, and 0.7 pbw di-butyl-tin dilaurate. A sex composition was prepared. This composition was an emulsion.

106.1 pbw of the polyisocyanate mixture and 46.9 pbw of the isocyanate-reactive composition (isocyanate index 75.5) were mixed using a Heidolph ^™ mechanical mixer for 13 seconds at a speed of 5000 revolutions per minute (rpm). After mixing, the reaction mixture was poured into an open 5 liter bucket and allowed to react. Prior to injecting the reaction mixture into the container, a release agent Desmotrol ^™ D-10RT was applied to the inner wall of the container. 2.5 minutes after the foam stopped expanding (foam expansion time 70 seconds), the foam was removed from the container and cooled to ambient temperature. A rigid polyurethane foam was obtained. Next, a core foam sample was cut from the center of the foam for property evaluation. The free rise core density was 11 kg / m ³ (ISO / DIS 845). The sample was then crushed by compression (70% CLD) once in the direction of expansion using an Instron ^™ mechanical tester fitted with a flat plate.

After crushing, a flexible foam was obtained that had no major glass-rubber transition from -100 ° C to + 25 ° C and had the following properties:
Free rise core density (ISO / DIS 845, kg / m ³ ) 13
Rebound resilience (ISO 8307,%), measured in the crushing direction 59
Tensile strength at break (ISO-1798, kPa) 71
Elongation at break (ISO-1798,%) 30
Tearing strength (ISO / DIS 8067, N / m) 70
Compression set (ISO 1856, Method A,%) 38
CLD-25% (ISO 3386/1, kPa) 3.2
(CLD = compression load deflection)
CLD-40% (ISO 3386/1, kPa) 5.2
CLD-65% (ISO 3386/1, kPa) 18.3
CLD sag coefficient (ISO 3386/1) 5.7
CLD hysteresis loss (ISO 3386/1,%) 48
tanδ _max (−100 ° C. to + 25 ° C.) (ISO / DIS 6721-5) 0.06
Oxygen index (ASTM 2863,%) 20.5
Young storage modulus ratio E ′ (−100 ° C.) / E ′ (+ 25 ° C.) (ISO / DIS 6721-5) 2.0
Young's storage modulus (25 ° C) (ISO / DIS 6721-5, kPa) 180
Benzene content, weight% (calculation) 43.5
Compressed foam properties were measured in the direction of foam expansion / collapse.

Measurements were performed according to ISO / DIS 6721-5 with a Rheometric Scientific DMTA apparatus using a DMTA test 3-point bending mode. The sample specimen size was 1.0 cm long, 1.3 cm wide, and 0.4 cm thick. Applied strain amplitude 64 × 10 ⁻⁴ cm, frequency 1 Hz, heating rate 3 ° C./min. Foam samples were preconditioned at 23 ° C./50% RH for 24 hours prior to testing. The foam sample was quenched to −120 ° C. (cooling rate 8.5 ° C./min) and maintained at this temperature for 5 minutes before starting sample heating.

Example 2
Three types of isocyanate-reactive blends (Blend A, B, C) were prepared.
Blend A was prepared by mixing 200 pbw of the EO / PO polyol of Example 1 with 6.5 pbw “DABCO” T9 (a catalyst from AIR PRODUCTS, DABCO is a trademark). Blend B was prepared by mixing 75.5 pbw of polyethylene glycol of molecular weight 200 and 5.56 pbw of “IRGANOX” 5057 (an antioxidant from Ciba-Geigy, IRGANOX is a trademark). Blend C was prepared by mixing 23.5 pbw triethylene glycol, 40.0 pbw water, and 0.6 pbw monobasic sodium phosphate.

A "Ytron" (TM) mechanical mixer comprising 166.1 pbw of blend A, 65.2 pbw of blend B, 51.6 pbw of blend C, and 617.1 pbw of the isocyanate blend of Example 1 (isocyanate index 100) For 13 seconds at a speed of 3500 rpm. After mixing, the reaction mixture was poured into an open 50 × 50 × ³⁰ cm ³ wooden mold. The inner wall was covered with paper before pouring the reaction mixture into the wooden mold. One hour after the foam stopped expanding (foam expansion time 70 seconds), the foam was removed from the container and cooled to ambient temperature. A rigid polyurethane foam was obtained. The foam was cut and crushed as in Example 1.

The free rise core density before crushing was 13 kg / m ³ .
After crushing, a flexible foam was obtained that had no major glass-rubber transition from -100 ° C to + 25 ° C and had the following properties:
Free rise core density (kg / m ³ ) 15
Rebound resilience (%) 62
Tensile strength at break (kPa) 67
Elongation at break (%) 49
Compression set (%) 31
CLD-40% 7.1
Young storage modulus ratio [E ′ (−100 ° C.) / E ′ (+ 25 ° C.)] 2.8
Young's storage modulus (kPa) 158
Benzene content, wt% (calculated) 42.6
Example 3
Two types of isocyanate-reactive blends (blends A and B) were prepared. Blend A mixes 30 pbw of the EO / PO polyol of Example 1 with 0.3 pbw “DABCO” T9 and 0.3 pbw of 1-methyl-1-oxo-phospholene (carbodiimide catalyst from Hoechst). It was prepared by. Blend B was prepared by mixing 11.3 pbw of 200 molecular weight polyethylene glycol, 1.95 pbw of diethanolamine, 1.58 pbw of ethylene glycol, and 4.5 pbw of water.

26.9 pbw of blend A, 17.3 pbw of blend B and 108.6 pbw of the isocyanate blend of Example 1 (isocyanate index 123) using a Heidolph ^™ mechanical mixer at a speed of 5000 revolutions per minute (rpm). For 13 seconds. After mixing, the reaction mixture was poured into an open 5 liter container and allowed to react. One hour after the foam stopped expanding (foam expansion time 70 seconds), the foam was removed from the container and cooled to ambient temperature. A rigid polyurethane foam having a free rise density of 16 kg / m ³ was obtained. Attenuated total reflection Fourier transform infrared analysis showed the presence of a carbodiimide group (signal at 2140 cm ⁻¹ ).

After crushing, as described in Example 1, a flexible foam having the following properties was obtained without having a major glass-rubber transition at −100 ° C. to + 25 ° C. (Test method is the same as Example 1) :
Free rise core density (kg / m ³ ) 18
Rebound resilience (%) 48
Young storage modulus ratio [E ′ (−100 ° C.) / E ′ (+ 25 ° C.)] 2.5
Young's storage modulus (kPa) 126
Benzene content, wt% (calculated) 42.9

Claims (4)

Polyisocyanate (1), polyol (2) having a hydroxyl number of at least 150 mg KOH / g and an average nominal hydroxyl functionality of 2 to 8, a hydroxyl number of 10 to less than 150 and an average nominal hydroxyl of 2 to 6 A method for producing a rigid polyurethane foam by reacting a polyol (3) having a functionality with water,
The amount of polyol (2), polyol (3) and water (per 100 parts by weight of polyisocyanate, polyol (2), polyol (3) and water) is 2 to 20 parts by weight, 5 to 35 parts by weight and 1 to 1, respectively. The above process, wherein the content is 17 parts by weight, and the polyol (3) is a polyoxyethylene polyoxypropylene polyol having an oxyethylene content of 20% by weight or more. Compound (2): Compound (3) the weight ratio of 0.1-4: 1, The method of claim 1. Free rise core density of the foam is 3~27kg / ^{m 3,} The method of any of claims 1-2. Free rise core density of the foam is 3~18kg / ^{m 3,} The method of any of claims 1-2.